The distribution of echinostome parasites in ponds and implications for larval anuran survival.

Parasites can influence host population dynamics, community composition and evolution. Prediction of these effects, however, requires an understanding of the influence of ecological context on parasite distributions and the consequences of infection for host fitness. We address these issues with an amphibian - trematode (Digenea: Echinostomatidae) host-parasite system.

Echinostome-induced mortality varies across amphibian species in the field.

Echinostomes are receiving increased attention because of their emerging parasite status in landscapes associated with human development and their ability to infect and kill many North American larval amphibians. While laboratory experiments have shown that echinostomes can cause extensive mortality in their amphibian hosts, their effect on tadpoles in the field is less clear. I conducted a controlled-infection field-enclosure experiment in 4 ponds to compare the effects of echinostomes on green frog (Rana clamitans) and gray tree frog (Hyla versicolor) tadpoles in the field.

Echinostome metacercariae cyst elimination in Rana clamitans (green frog) tadpoles is age-dependent.

Host response to parasite exposure is an important determinant of the outcome of host-parasite interactions. Factors such as host body condition and age can strongly influence host response to parasites and infection. This study followed Echinostoma revolutum infection levels in larval green frogs (Rana clamitans) exposed at 2 different ages.

A role for CCAAT/enhancer-binding protein beta in the basal regulation of the distal-less 3 gene promoter in placental cells.

The homeodomain protein Distal-less 3 (Dlx3) is essential for normal placental development in mice. Dlx3-null mice die by embryonic day 10.0 due to placental failure.